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Professor Program
Activity: Worksheet for Mitosis and Meiosis
Lecture Concept
Chromosome structure, mitosis and meiosis
Activity Type
Group work with worksheet
Time Needed in Discussion
50 minutes
Purpose
• To emphasize the complexity of meiosis
• To provide the students an opportunity to learn the terminologies of genetics, i.e.,
homologous chromosome, diploid, haploid, etc.
Abstract
Pre-class prep
Teacher asks questions regarding chromosomes and synthesis
Groups demonstrate mitosis
Groups demonstrate meiosis
30 min
10 min
5 min
25 min
Supplies
ƒ Teacher demonstration set of chromosomes (pipe-cleaner or magnetic versions – see other
activities for ideas).
ƒ Worksheet (similar to attached)
Pre-class prep
ƒ Create demonstration chromosomes
ƒ Create worksheet to fit lecture material (a sample is attached).
In Class
This worksheet follows the usual model that breaks up group
work and teacher mini-lectures into small chunks.
Arrange students into groups of 2-4 students, and have them
turn chairs to face each other. Direct them to take out their
worksheets and lecture notes and begin working on question 1.
As the discussion leader, spend this time wandering between the
groups. Encourage quiet members to speak, praise good
answers. Offer probing questions if you see a group going in
the wrong direction.
After the groups have worked on the first question (about 10
minutes, usually), return to the front of the room. If students
General Teaching Tip:
Printing Worksheets
Have paperwork you want the
students to use in class?
Create a class web page and
post the pages to the page by
10pm the night before.
Students can print up whatever
you want them to bring and
bring it to class. Don’t bring
spares after the first week, or
they will depend on those.
© 2007 by the HHMI-UCIrvine Professor Program. For non-commercial, educational use only.
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Professor Program
had trouble with the question, set up your demonstration chromosomes to the “question” state,
and ask students to guide you to the “answer” state. Elicit student responses and guide them
to appropriate figures or lecture note pages to help them find these correct responses. It will
take longer than you providing a straight lecture, but students will remember the answers
better.
After you have worked together on the first section, have students return to group work for the
next section. Follow the same pattern of group work and then leader-facilitated answers. If
you feel a concept requires a lecture explanation, make sure your “mini” lecuture is five
minutes or less.
Things to Emphasize
ƒ Chromsomes are single stranded before S phase. After S phase, the chromosomes
become double-stranded.
ƒ In Mitosis during Metaphase, the chromosomes line up on the metaphase plate, but
without their homologues. In Meiosis during Metaphase I, the tetrads line up on the
metaphase plate. Then it’s back to double-stranded chromosomes lining up in
Metaphase II.
ƒ The phases in which tetrads appear and disappear.
ƒ How crossing over makes different combinations of genes/alleles on a chromosome.
ƒ The first division of Meiosis creates haploid duaghter cells; the change in ploidy
occurs in first division of Meiosis
ƒ Make sure the students can define and discuss these terms: haploid, diploid,
homologous chromosomes, alleles, tetrad, sister chromatids, chromatid, gene,
independent assortment, crossing over, and genetic variation.
A comment about teaching meiosis: Students THINK they understand meiosis. They think
it’s just mitosis twice. But year after year I have found that students AND SOME
DISCUSSION LEADERS do not understand the difference between meiosis and mitosis.
They don’t realize that metaphase 1 is profoundly different than metaphase 2. They confuse
chromatids and chromosomes. And they do not understand that the first division changes
ploidy. So if any worksheet seems incorrect, ASK FOR HELP before teaching your students.
Copyright 2007: This activity was created by Adrienne Williams and edited by Masa
Kinoshita and Adrienne Williams
© 2007 by the HHMI-UCIrvine Professor Program. For non-commercial, educational use only.
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Professor Program
Sample Chromosome Worksheet
A 2n = 4 cell has chromosomes that look like this:
1. Draw what the cell looks like after S phase. Label one of the
following:
• chromatid
• pair of sister chromatids
• chromosome
How many chromosomes are in the cell now? ________
(stop here and wait for your instructor)
2. What will this cell look like during Metaphase of mitosis?
What will this cell look like during the following stages of meiosis?
Metaphase I
II
Telophase I
Metaphase II
Telophase
3. In the cells above, write an “n” next to the cells that are haploid. Does the first or second
division cause haploidy?
© 2007 by the HHMI-UCIrvine Professor Program. For non-commercial, educational use only.